* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Microsoft YaHei', sans-serif;
    line-height: 1.6;
    background-color: #f5f5f5;
    color: #333;
    padding-bottom: 6rem;
    position: relative;
    overflow-x: hidden;
}

.background-decoration {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    overflow: hidden;
}

.circle {
    position: absolute;
    border-radius: 50%;
    opacity: 0.1;
}

.circle-1 {
    width: 600px;
    height: 600px;
    background: linear-gradient(45deg, #3498db, #2ecc71);
    top: -200px;
    right: -200px;
}

.circle-2 {
    width: 400px;
    height: 400px;
    background: linear-gradient(45deg, #e74c3c, #f39c12);
    bottom: -100px;
    left: -100px;
}

.circle-3 {
    width: 300px;
    height: 300px;
    background: linear-gradient(45deg, #9b59b6, #3498db);
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

header {
    background-color: rgba(44, 62, 80, 0.95);
    color: white;
    padding: 2rem 0;
    text-align: center;
    box-shadow: 0 2px 15px rgba(0,0,0,0.1);
    backdrop-filter: blur(10px);
}

.logo {
    display: flex;
    align-items: center;
    justify-content: flex-start;
    gap: 2rem;
    padding: 0 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.logo-text {
    text-align: left;
}

.logo-icon {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-left: 2rem;
}

.logo-icon i {
    font-size: 2rem;
    color: #fff;
    text-shadow: 0 2px 5px rgba(0,0,0,0.2);
}

.logo-icon i:nth-child(2) {
    font-size: 1.5rem;
    color: #3498db;
}

.logo h1 {
    font-size: 2.2rem;
    font-weight: 600;
    letter-spacing: 1px;
    background: linear-gradient(45deg, #3498db, #2ecc71);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.1);
    margin: 0;
}

.subtitle {
    font-size: 1.1rem;
    color: #bdc3c7;
    letter-spacing: 2px;
    margin-top: 0.2rem;
}

.container {
    max-width: 1200px;
    margin: 2rem auto;
    padding: 0 1rem;
}

.conversion-panel {
    background: rgba(255, 255, 255, 0.95);
    border-radius: 15px;
    box-shadow: 0 2px 20px rgba(0, 0, 0, 0.1);
    padding: 2rem;
    display: flex;
    gap: 2rem;
    align-items: stretch;
    backdrop-filter: blur(10px);
    margin-bottom: 3rem;
}

.input-section,
.output-section {
    flex: 2;
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.convert-section {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1rem;
}

h2 {
    color: #2c3e50;
    font-size: 1.5rem;
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

h2 i {
    color: #3498db;
}

.format-selector select {
    width: 100%;
    padding: 0.8rem;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    font-size: 1rem;
    color: #2c3e50;
    background-color: white;
    cursor: pointer;
    transition: all 0.3s ease;
}

.format-selector select:hover {
    border-color: #3498db;
}

.drop-zone {
    flex: 1;
    border: 2px dashed #2c3e50;
    border-radius: 12px;
    padding: 2rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    min-height: 200px;
    background-color: rgba(44, 62, 80, 0.02);
}

.drop-zone i {
    font-size: 3rem;
    color: #2c3e50;
    transition: all 0.3s ease;
}

.drop-zone:hover {
    background-color: rgba(44, 62, 80, 0.05);
    border-color: #3498db;
    transform: translateY(-2px);
}

.drop-zone:hover i {
    color: #3498db;
    transform: scale(1.1);
}

.drop-zone.drag-over {
    background-color: rgba(52, 152, 219, 0.1);
    border-color: #3498db;
    transform: scale(1.02);
}

.file-info {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.8rem 1.2rem;
    background-color: #f8f9fa;
    border-radius: 8px;
    font-size: 0.9rem;
    box-shadow: 0 2px 5px rgba(0,0,0,0.05);
}

.file-info i {
    font-size: 1.2rem;
    color: #3498db;
}

.convert-btn {
    padding: 1rem 2rem;
    background: linear-gradient(45deg, #3498db, #2ecc71);
    color: white;
    border: none;
    border-radius: 50px;
    cursor: pointer;
    font-size: 1.2rem;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 0.8rem;
    box-shadow: 0 4px 15px rgba(52, 152, 219, 0.3);
}

.convert-btn i {
    font-size: 1.4rem;
}

.convert-btn:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(52, 152, 219, 0.4);
}

.convert-btn:disabled {
    background: #95a5a6;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.output-preview {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    padding: 2rem;
    background-color: rgba(44, 62, 80, 0.02);
    border-radius: 12px;
    min-height: 200px;
    border: 2px dashed #e0e0e0;
}

.output-preview i {
    font-size: 3rem;
    color: #2c3e50;
    opacity: 0.5;
}

.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.feature-item {
    background: rgba(255, 255, 255, 0.95);
    padding: 2rem;
    border-radius: 12px;
    text-align: center;
    box-shadow: 0 2px 15px rgba(0,0,0,0.1);
    transition: all 0.3s ease;
    backdrop-filter: blur(10px);
}

.feature-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 20px rgba(0,0,0,0.15);
}

.feature-item i {
    font-size: 2.5rem;
    color: #3498db;
    margin-bottom: 1rem;
}

.feature-item h3 {
    color: #2c3e50;
    margin-bottom: 0.5rem;
    font-size: 1.3rem;
}

.feature-item p {
    color: #7f8c8d;
    font-size: 0.9rem;
}

footer {
    text-align: center;
    padding: 1.5rem;
    background-color: rgba(44, 62, 80, 0.95);
    color: white;
    position: fixed;
    bottom: 0;
    width: 100%;
    box-shadow: 0 -2px 10px rgba(0,0,0,0.1);
    backdrop-filter: blur(10px);
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

.footer-links {
    display: flex;
    gap: 1rem;
}

.footer-links a {
    color: white;
    text-decoration: none;
    font-size: 1.2rem;
    transition: all 0.3s ease;
}

.footer-links a:hover {
    color: #3498db;
    transform: translateY(-2px);
}

@media (max-width: 768px) {
    .conversion-panel {
        flex-direction: column;
    }
    
    .convert-section {
        padding: 1rem 0;
    }
    
    .convert-btn {
        width: 100%;
        justify-content: center;
    }
    
    .logo {
        flex-direction: column;
        gap: 1rem;
        padding: 0 1rem;
    }

    .logo-text {
        text-align: center;
    }

    .logo-icon {
        margin-left: 0;
    }

    .logo h1 {
        font-size: 1.8rem;
    }
    
    .subtitle {
        font-size: 1rem;
    }
    
    .footer-content {
        flex-direction: column;
        gap: 1rem;
    }
    
    .circle-1 {
        width: 300px;
        height: 300px;
    }
    
    .circle-2 {
        width: 200px;
        height: 200px;
    }
    
    .circle-3 {
        width: 150px;
        height: 150px;
    }
} 